I would like to create a column based on the last non-null value of another column from different ids (groups).
For example, from possession of these dice:
Obtained through:
structure(list(id = c(1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3,
3, 3, 4, 4, 4, 4, 4), select = c(1, 0, 0, 2, 0, 0, 0, 0, 1, 0,
3, 5, 0, 0, 0, 2, 0, 0, 0, 0)), class = c("tbl_df", "tbl", "data.frame"
), row.names = c(NA, -20L))
I would like to get something like:
I appreciate any help.
>Solution :
Grab the last() value .by= each group, after only looking at values which are != 0:
library(dplyr)
dat %>%
mutate(result = last(select[select != 0]), .by=id)
### A tibble: 20 × 3
## id select result
## <dbl> <dbl> <dbl>
## 1 1 1 2
## 2 1 0 2
## 3 1 0 2
## 4 1 2 2
## 5 1 0 2
## 6 2 0 1
## 7 2 0 1
## 8 2 0 1
## 9 2 1 1
##10 2 0 1
##11 3 3 5
##12 3 5 5
##13 3 0 5
##14 3 0 5
##15 3 0 5
##16 4 2 2
##17 4 0 2
##18 4 0 2
##19 4 0 2
##20 4 0 2